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Fats and Oils – Everything You Need to Know

The basics of fats and oils

Fats – hardly any other topic dominates the headlines in health magazines as much as “fat”. And most of us immediately think of something negative when we hear that word. There is hardly any other topic where there is so much dangerous, superficial knowledge and thus widespread confusion. Similar to carbohydrates, one reads and hears everywhere that one should either eat as many of them as possible or avoid them like the plague. “Fat makes you fat!” Is that really true? And if it’s not, what is true then?

I’ll tell you what’s really behind the mystery of fats and what science says, far away from the marketing strategies of various food manufacturers. Why are fats essential to us? Plus, I’ll tell you why, above all, your heart will thank you for eating high-quality fats!

What are fats?

Fats are generally called “lipids” in nutritional science, which together with carbohydrates and proteins form the three cornerstones of our diet. Together they make up the three macronutrients. From a chemical point of view, fats are so-called “esters” of the alcohol glycerol, which is why such compounds are also called triglycerides (“tri” / triple esters of glycerol). Lipids therefore always consist of a combination of fatty acids and glycerol. They consist of a group of organic substances of biological origin and dissolve well in solvents such as methanol, but dissolve only poorly or not at all in water. In industry, fats are mainly used as fuels and in the manufacture of plastics. This is also one of the reasons why plastic is made from petroleum, which is also a type of “fat or oil” (“polyester”).

What are the differences between saturated, monounsaturated, and polyunsaturated fatty acids?

Fatty acids consist of a chain of 2-30 carbon atoms, which usually have two hydrogen atoms attached. If each carbon atom in the chain has its maximum number of hydrogen atoms, the fatty acid is “saturated”. If one hydrogen atom is missing, it is “monounsaturated” and if several are missing, it is “polyunsaturated”. Instead of the “missing” hydrogen atoms, we find a double bond between two carbon atoms. So, this double bond creates a small kink in the fatty acid chain. Normally, food consists of a mixture of different fatty acids with different numbers of hydrogen atoms. The well-known representatives of omega-3 and omega-6 fatty acids also belong to the polyunsaturated fatty acids. Their numbers stand for the point in the fatty acid chain at which the first double bond between two carbon atoms exists and thus a kink can be found in the chain.

You can see, the more saturated fat food has, the “stiffer” it is because it has no kinks. Therefore, lipids that are high in saturated fatty acids, e.g. butter, are usually solid at room temperature. You can think of a saturated fatty acid like a stiff stick. Monounsaturated fatty acids have one “missing” hydrogen atom, i.e. one kink. This makes it a little more flexible. As a consequence, fats with a high amount of mono- or polyunsaturated fatty acids are usually more flexible due to the kinks. Thus, they are more fluid at room temperatures, such as olive oil. The more unsaturated fatty acids are, the more flexible the fat is. Fats and oils are categorized depending on where these kinks are and how many (un)saturated spots a fatty acid has.

What is the difference between fats and oils?

Oils are nothing more than fats that are liquid at room temperature. That is actually the main difference. Jokingly, that’s also my personal yardstick: It’s finally summer when the coconut fat turns into coconut oil! 😉

In fact, numerous studies have shown that, for example, a single fast food meal, typically high in saturated fats, stiffens our arteries within a few hours. This effect can last for several hours to days. Fast food meals and highly processed foods in general have saturated, ie “stiff” fatty acid structures that find their way into your body through eating.

Fats and oils are essential but everything in moderation
Fats and oils are essential but everything in moderation

What is the function of lipids?

First and foremost, lipids serve as fuel and thus as an energy supplier in the human body. With 9.3 kcal per gram, they provide more than twice as much energy than the same amount of carbohydrates or proteins. It is also construction material for cells and membranes, an insulator (fat layer for thermal insulation), and fulfills other special tasks. This includes the tasks as a transporter for fat-soluble vitamins (A, D, E, and K), signal substance for body functions, and for our brain (steroid hormones and tissue hormones), cofactors or works as visual pigments. In addition, fats are vital, without them our body cannot function, as fats control and even enable vital processes.

For example, our organs are also surrounded by a pressure pad made of fat, which protects our organs like a kind of cotton wool layer. Otherwise, our organs would jump around uncoordinatedly with every single step. In the same way, this layer of fat also protects all other vessels in our body. Polyunsaturated fatty acids in particular are very important for this, as they also keep our cells supple due to their smooth, flexible construction. Our cells are more mobile and nutrients, vitamins and glucose get through more easily than with saturated fatty acids, which tend to leave a stiff layer.

Not to be forgotten is the fat layer “depot fat”, which acts as energy storage. This function has lost importance over time, but that was also vital for our ancestors in winter and in famine. Outside of the body, fats mainly serve as flavor carriers.

What happens when we eat too much or insufficiently fat?

Deficiency symptoms have numerous manifestations. They range from skin eczema, anemia, visual disturbances, increased dandruff, headache / abdominal pain, muscle weakness, tremors to severe hormonal restrictions, schizophrenia, depression, high blood pressure, Crohn’s disease, heart disease, and severe mood swings. Anorexic girls and women, for example, do not have a regular menstrual cycle because they do not have enough fat tissue, nor they eat enough fat, to produce the necessary hormones. Since many vitamins can only be absorbed through the simultaneous intake of fats (fat-soluble vitamins), a deficiency in fat absorption is also accompanied by a vitamin deficiency.

Nevertheless, in today’s diet, too much fat tends to be the problem. The consequences here range from severe cholesterol levels to obesity, arteriosclerosis, and an increased risk of heart attacks and strokes. In addition to cardiovascular diseases, there are also rheumatoid arthritis, osteoporosis, and tumor diseases. The problem here is that “unhealthy fats” make our vessels really greasy, “stiffen”, and so too little blood can flow through them.

In order to be able to pump the same amount of blood through our body, our heart has to work a lot harder, which can overstress it. You can imagine this using a garden hose. Hold the end a little closed. Pretty quickly you will notice that you are feeling a higher pressure – it is similar to our body: The blood pressure rises and with it, all the pressure rises in our body and on our vessels. There is also a strong scientific suspicion that eating too much fat can lead to cancer and diabetes.

What is the recommendation for the daily intake of fats?

There is no specific definition of a fat requirement in nutritional science. There is only a guideline value for the maximum limit of fat intake, which is around 30% of food energy. This is to guarantee that important vitamins, trace elements, minerals, fiber and also essential proteins are absorbed with the remaining 70%. This is the only way to have a balanced diet. Babies and infants up to one year of age have an increased need for fat, which is, however, perfectly covered by the very nutrious, high-fat breast milk.

Our body can produce most of the fatty acids. There are only two fatty acids that are essential for survival: linoleic acid (omega-6) and alpha-linolenic acid (omega-3). They are also known as omega-3 and omega-6 fatty acids. The right ratio is also very important here. A higher consumption of omega-3 fatty acids is recommended; in fact, it would be best if you eat 11x as many omega-3 as omega-6 fatty acids! Before you start doing great maths about how much of what to eat, the easiest thing to do is to pay attention to eating foods that are particularly high in omega-3 fatty acids. I will provide you a list of them in one of the following blog posts. Stay tuned! 😉

What do the different types of fatty acids do?

Saturated fatty acids and thus fatty acids that you should avoid in your diet can be found mainly in animal and heavily processed, fried products. This includes above all butter, cheese, cream, eggs, meat, and sausage. A characteristic of saturated fatty acids, for example, is a rather firm consistency and a high melting point. Animal fats in particular, which are rich in saturated fatty acids, are strongly suspected of causing the (bad) LDL cholesterol level to rise. This goes hand in hand with an increased risk of coronary heart disease. However, there are also “good” saturated fatty acids such as coconut oil, as this also contains many vitamins, minerals, and trace elements.

You can find monounsaturated fatty acids mainly in plant-based foods such as rapeseed oil, olive oil, avocados, nuts, and seeds. In particularly warm temperatures, you will see some foods “sweat”. This means that the fatty acids it contains come closer to their melting point. Studies show that monounsaturated fatty acids have a positive effect on our bodies. They have a balancing effect on the cholesterol level, prevent arteriosclerosis, and generally lower blood lipid levels.

Polyunsaturated fatty acids have many positive effects

Omega-3 and omega-6 fatty acids are probably the best-known representatives of the polyunsaturated fatty acids. You can only consume these two essential fatty acids through your diet. So, your body cannot produce them by itself. They are the main component of cell membranes and provide the basis, among other things, for your tissue hormones to be produced. These play a key role in your water balance, insulin metabolism, the immune system, and inflammation processes. Omega-3 has different functions than omega-6, which is why the correct ratio of both is important. Strictly speaking, a distinction must also be made between the various omega-3 (ALA, EPA, DHA) and omega-6 fatty acids (LA and AA). In order not to go beyond the scope, I will dedicate a separate blog post to this topic.

Ideally, you should pay attention to fats and oils that are high in omega-3. Particularly good vegetable sources of omega-3 fatty acids are linseed oil, soybean oil, microalgae oil, and rapeseed oil, but also linseed, chia seeds, and walnuts. You can find omega-6 fatty acids mainly in hemp oil, evening primrose oil, safflower oil, and sunflower oil. Theoretically, our body can also convert omega-6 fatty acids into omega-3 fatty acids. This mechanism only works under very special circumstances, and more on that soon.

Walnuts are a great source of polyunsaturated fatty acids!
Walnuts are a great source of polyunsaturated fatty acids!

Why is it important to eat high quality fats?

Since lipids are not water-soluble, they cannot easily be absorbed from the intestine into the blood. It would immediately clog the fine walls of the small intestine and swim in our veins like grease eyes in the water. Therefore, the fat we eat is absorbed by the lymphatic system, which transports important fluids and immune cells parallel to our bloodstream. All lymph vessels converge to the main vessel (ductus thoracicus), which takes over the fat absorption in the small intestine.

As soon as the ductus has filled with tiny fat droplets, these take their way through the diaphragm directly into the heart. Directly to the heart. Without detours via detoxification organs. This is exactly why it is so important to eat good quality oil. Cheap deep-frying fat from fast-food chains gets straight to the heart, unfiltered, just as high-quality, cold-pressed olive oil and can easily be deposited there. This is one of the main reasons why an incorrect diet with too much saturated fatty acids can lead to severe cardiovascular diseases and heart attacks.

Not only the origin but also the manufacturing process is decisive for the quality of the fats and oils. The more processed, refined, deodorized, bleached and hardened a fat or oil is, the less healthy it is, the more nutrients are lost and the more trans fats are created.

What are trans fatty acids?

Probably all of us have heard of the term “trans fatty acids”. And mostly in a negative context. Trans fatty acids can have harmful effects in larger quantities. You can find these mainly in dairy products and meat, but also with the wrong use of oils. In addition, they often arise when barbecuing and are visible as “black or burnt spots”. They usually arise when fats and oils are cooked too hot, generally when industrial processing is carried out to extend the shelf life of food or when fats are hardened to make them easy to spread. In the case of trans fatty acids, in the course of processing – to put it simply – some hydrogen atoms end up in the wrong place, hence the name “trans” fatty acid.

As a rule, you should avoid the consumption of trans fats, as they are associated with increased LDL cholesterol, an increased risk of arteriosclerosis and coronary heart disease. Trans fats stiffen our cell walls, stimulate inflammatory processes in the body and can also lead to insulin resistance, a precursor to diabetes. Trans fats have shown in numerous studies: They actually make you fat and sick! By avoiding (heavily) processed foods, using organic and high-quality fats and oils, and distinguishing between oils for hot and cold preparation when cooking, you shouldn’t have any problems here. More about this soon.

You can find trans fats mainly in fried and processed foods such as potato chips, french fries, salad croutons, cookies, cake mixes, many ready-to-eat meals, pastries made of puff pastry, artificially hardened products with palm oil, sausages, and many sweets. As you can see, you will find trans fats mainly in industrial, processed products, which anyway have no place in a balanced, whole-food nutrition and should rather be an exception.

Vegetable fats are healthier than animal fats

A kind of rule of thumb for oils, fats, and fatty acids is: Unsaturated fatty acids are healthier than saturated ones. Plant-based fats are generally healthier than animal fats. You should avoid trans fats entirely. I will give you more information about omega-3 and omega-6, as well as the correct use of fats and oils during preparation, shortly! Stay tuned! 🙂

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Sources for this blogpost

Bozzatello, P./Brignolo, E./De Grandi, E./Bellino, S. 2016: Supplementation with Omega-3 Fatty Acids in Psychiatric Disorders: A Review of Literature Data, in: Journal of Clinical Medicine, Vol. 5, 2016, No. 8, p. 67.

Kavanagh, K. et al. 2007: Trans Fat Diet Induces Abdominal Obesity and Changes in Insulin Sensitivity in Monkeys, in: OBESITY, Vol. 15, 2007, No, 7, pp. 1675-1684.
https://onlinelibrary.wiley.com/doi/epdf/10.1038/oby.2007.200

Larqué, E./Gil-Sánchez, A./Prieto-Sanchez, M. T./Koletzko, B. 2012: Omega 3 fatty acids, gestation and pregnancy outcomes, in: British Journal of Nutrition, Vol. 107, 2012, No. 2, pp. 77-84.

The American Society for Biochemistry and Molecular Biology 2012: Essential Fatty Acids – The Work of George and Mildred Burr, in: The Journal of Biological Chemistry, Vol. 287, 2012, No. 2, pp. 35429-35441.

Tortosa-Caparrós, E./Navas-Carrillo, D./Marín, F./Orenes-Piñero, E. 2017: Anti-inflammatory effects of omega 3 and omega 6 polyunsaturated fatty acids in cardiovascular disease and metabolic syndrome, in: Critical Reviews of Food Science Nutrition, Vol. 57, 2017, No. 16, pp. 3421-3429.

Vogel, R. A./Corretti, M. C./Plotnick, G. D. 1997: Effect of a single high-fat meal on endothelial function in healthy subjects, Vol. 79, 1997, No. 3, pp. 350-354.

Wang, D. D. et al. 2016: Association of Specific Dietary Fats With Total and Cause-Specific Mortality, in: JAMA Internal Medicine, Vol. 176, 2016, No. 8, pp. 1134-1145.
https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2530902

Willett, W. C. 2001: Eat, drink, and be healthy – the Harvard Medical School guide to healthy eating, New York, 2001.

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